Merge branch 'pr-196'

This adds support for the --send-size parameter as both a test parameter
and a global parameter. The parameter is supposed to be per-flow, but this
thus far only works on the multi-host rtt_fair-based tests. However, this
is not unique to this new parameter, so let's not hold up merging because
of this.

Closes #196.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>

doc/options.rst

@@ -217,6 +217,17 @@ parsing input files.
    can be measured. As such you may need to adjust it if you are experiencing
    latency above the default value. Set to 0 to disable.
 
+.. option:: --send-size=SEND_SIZE
+
+    Send size (in bytes) used for TCP tests. Netperf uses the socket buffer size
+    by default, which if too large can cause spikes in the throughput results.
+    Lowering this value will increase CPU usage but also improves the fidelity
+    of the throughput results without having to decrease the socket buffer size.
+
+    Can be specified multiple times, with each value corresponding to a stream
+    of a test. If only specified once, the same value will be applied to all
+    flows.
+
 .. option:: --test-parameter=key=value
 
    Arbitrary test parameter in key=value format. Key will be case folded to

flent/runners.py

@@ -956,6 +956,9 @@ def check(self):
         args.setdefault('cong_control',
                         self.settings.TEST_PARAMETERS.get('tcp_cong_control', ''))
         args.setdefault('socket_timeout', self.settings.SOCKET_TIMEOUT)
+        args.setdefault('send_size',
+                        self.settings.SEND_SIZE[0]
+                        if self.settings.SEND_SIZE else None)
 
         if self.settings.SWAP_UPDOWN:
             if self.test == 'TCP_STREAM':
@@ -1030,6 +1033,8 @@ def check(self):
 
         if self.test in ("TCP_STREAM", "TCP_MAERTS"):
             args['format'] = "-f m"
+            if args['send_size']:
+                args['send_size'] = "-m {0} -M {0}".format(args['send_size'])
             self.units = 'Mbits/s'
 
             if args['test'] == 'TCP_STREAM' and self.settings.SOCKET_STATS:
@@ -1050,7 +1055,7 @@ def check(self):
                        "{marking} -H {control_host} -p {control_port} " \
                        "-t {test} -l {length:d} {buffer} {format} " \
                        "{control_local_bind} {extra_args} -- " \
-                       "{socket_timeout} {local_bind} -H {host} -k {output_vars} " \
+                       "{socket_timeout} {send_size} {local_bind} -H {host} -k {output_vars} " \
                        "{cong_control} {extra_test_args}".format(**args)
 
         super(NetperfDemoRunner, self).check()

flent/settings.py

@@ -368,6 +368,16 @@ def __call__(self, parser, namespace, values, option_string=None):
     "detected to support this (requires netperf version 2.7 or newer). Set to 0 "
     "to disable.")
 
+test_group.add_argument(
+    "--send-size",
+    action="append", type=unicode, dest="SEND_SIZE",
+    help="Send size (in bytes) used for TCP tests. netperf uses the socket "
+    "buffer size by default, which if too large can cause spikes in the "
+    "throughput results. Lowering this value will increase CPU usage but "
+    "also improves the fidelity of the throughput results without having "
+    "to decrease the socket buffer size. Can be specified multiple times, "
+    "with each value corresponding to a stream of a test.")
+
 test_group.add_argument(
     "--test-parameter",
     action=Update, type=keyval, dest="TEST_PARAMETERS", metavar='key=value',
@@ -730,10 +740,12 @@ def update_implications(self):
         if self.DATA_DIR is None:
             self.DATA_DIR = os.path.dirname(self.OUTPUT) or '.'
 
-        # Backwards compatibility for when LOCAL_BIND could only be specified
-        # once - just duplicate the value
+        # For per-stream options, if only specified once duplicate them for each
+        # host so they apply to all flows
         if len(self.LOCAL_BIND) == 1 and len(self.HOSTS) > 1:
             self.LOCAL_BIND *= len(self.HOSTS)
+        if len(self.SEND_SIZE) == 1 and len(self.HOSTS) > 1:
+            self.SEND_SIZE *= len(self.HOSTS)
 
         for k, v in self.BATCH_OVERRIDE.items():
             if not hasattr(v, 'lower'):

flent/testenv.py

@@ -57,7 +57,12 @@
 # in the code below
 STREAM_CONFIG_PARAM_NAMES = ['label', 'ping_label', 'marking',
                              'control_host', 'local_bind', 'cc_algo',
-                             'udp_bandwidth', 'udp_pktsize']
+                             'udp_bandwidth', 'udp_pktsize', 'send_size']
+
+# Mapping of test parameters that will be picked up from the global settings if
+# they are not set
+GLOBAL_TEST_PARAMS_MAP = {'local_binds': 'LOCAL_BIND',
+                          'send_sizes': 'SEND_SIZE'}
 
 class _no_default():
     pass
@@ -155,6 +160,10 @@ def get_test_parameter(self, name, default=_no_default, split=False, cast=None):
                 ret = cast(ret)
             return ret
         except KeyError:
+            if name in GLOBAL_TEST_PARAMS_MAP:
+                ret = self.env[GLOBAL_TEST_PARAMS_MAP[name]]
+                if ret:
+                    return ret
             if default is not _no_default:
                 return default
             if self.informational:

flent/tests/rtt_fair.inc

@@ -34,7 +34,7 @@ DATA_SETS = o([
     ])
 
 def add_stream(i, host=None, label='BE', ping_label='ICMP', marking='CS0',
-               control_host=None, local_bind=None, cc_algo=None,
+               control_host=None, local_bind=None, cc_algo=None, send_size=None,
                length=LENGTH, delay=DELAY, **kwargs):
     if host is None:
         return
@@ -46,12 +46,12 @@ def add_stream(i, host=None, label='BE', ping_label='ICMP', marking='CS0',
      {'test': 'TCP_STREAM', 'length': length, 'host': host, 'marking': marking or
                               'CS0', 'control_host': control_host or host, 'local_bind': local_bind,
                               'delay': delay, 'id': host, 'units': 'Mbits/s', 'runner': 'netperf_demo',
-                              'cong_control': cc_algo}
+                              'cong_control': cc_algo, 'send_size': send_size}
     DATA_SETS['TCP download %s %s' % (label or "BE", host)] = \
      {'test': 'TCP_MAERTS', 'length': length, 'host': host, 'marking': marking or
                               'CS0', 'control_host': control_host or host, 'local_bind': local_bind,
                               'delay': delay, 'id': host, 'units': 'Mbits/s', 'runner': 'netperf_demo',
-                              'cong_control': cc_algo}
+                              'cong_control': cc_algo, 'send_size': send_size}
     DATA_SETS['Ping (ms) %s %s' % (ping_label or "ICMP", host)] = \
      {'ip_version': IP_VERSION, 'interval': STEP_SIZE, 'length': TOTAL_LENGTH,
       'host': host, 'local_bind': local_bind, 'id': host, 'units': 'ms',

man/flent.1

@@ -1,6 +1,6 @@
 .\" Man page generated from reStructuredText.
 .
-.TH "FLENT" "1" "July 09, 2019" "1.9.9-git" "Flent: The FLExible Network Tester"
+.TH "FLENT" "1" "February 11, 2020" "1.9.9-git" "Flent: The FLExible Network Tester"
 .SH NAME
 flent \- Flent: The FLExible Network Tester
 .
@@ -318,6 +318,18 @@ latency above the default value. Set to 0 to disable.
 .UNINDENT
 .INDENT 0.0
 .TP
+.B \-\-send\-size=SEND_SIZE
+Send size (in bytes) used for TCP tests. Netperf uses the socket buffer size
+by default, which if too large can cause spikes in the throughput results.
+Lowering this value will increase CPU usage but also improves the fidelity
+of the throughput results without having to decrease the socket buffer size.
+.sp
+Can be specified multiple times, with each value corresponding to a stream
+of a test. If only specified once, the same value will be applied to all
+flows.
+.UNINDENT
+.INDENT 0.0
+.TP
 .B \-\-test\-parameter=key=value
 Arbitrary test parameter in key=value format. Key will be case folded to
 lower case. The values are stored with the results metadata, and so can be